• Title, Summary, Keyword: Geant4

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Comparison Study on Low Energy Physics Model of GEANT4 (GEANT4 저 에너지 전자기 물리 모델에 대한 비교 연구)

  • Park, So-Hyun;Jung, Won-Gyun;Suh, Tae-Suk
    • Journal of Radiation Protection and Research
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    • v.35 no.3
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    • pp.124-134
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    • 2010
  • The Geant4 simulation toolkit provides improved or renewed physics model according to the version. The latest Geant4.9.3 which has been recoded by developers applies inserted Livermore data and renewed physics model to the low energy electromagnetic physics model. And also, Geant4.9.3 improved the physics factors by modified code. In this study, the stopping power and CSDA(Continuously Slowing Down Approximation) range data of electron or particles were acquired in various material and then, these data were compared with NIST(National Institute of Standards and Technology) data. Through comparison between data of Geant4 simulation and NIST, the improvement of physics model on low energy electromagnetic of Geant4.9.3 was evaluated by comparing the Geant4.9.2.

Evaluation of Lung Dose Using Linac Photon Beam in Geant 4 Simulation (Geant4 Simulation에서 Linac 광자선을 이용한 폐 선량평가)

  • Jang, Eun-Sung;Lee, Hyo-Yeong
    • Journal of the Korean Society of Radiology
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    • v.12 no.4
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    • pp.443-450
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    • 2018
  • The Geant 4 simulated the linear accelerator (VARIAN CLINAC) based on the previously implemented BEAMnrC data, using the head structure of the linear accelerator. In the 10 MV photon flux, Geant4 was compared with the measured value of the percentage of the deep dose and the lateral dose of the water phantom. In order to apply the dose calculation to the body part, the actual patient's lung area was scanned at 5 mm intervals. Geant4 dose distributions were obtained by irradiating 10 MV photons at the irradiation field ($5{\times}5cm^2$) and SAD 100 cm of the water phantom. This result is difficult to measure the dose absorbed in the actual lung of the patient so the doses by the treatment planning system were compared. The deep dose curve measured by water phantom and the deep dose curve calculated by Geant4 were well within ${\pm}3%$ of most depths except the build-up area. However, at the 5 cm and 20 cm sites, 2.95% and 2.87% were somewhat higher in the calculation of the dose using Geant4. These two points were confirmed by the geometry file of Genat4, and it was found that the dose was increased because thoracic spine and sternum were located. In cone beam CT, the dose distribution error of the lungs was similar within 3%. Therefore, if the contour map of the dose can be directly expressed in the DICOM file when calculating the dose using Geant4, the clinical application of Geant4 will be used variously.

An Integrated Framework Environment for Automatic Simulation of Geant4 : Geant4Editor (Geant4시뮬레이션 자동화를 위한 통합 프레임워크 환경 개발 : Geant4Editor)

  • Shin, Sung-Sik;Kim, A-Mi;Kim, Seung-Wan;Song, Ju-Whan;Gwun, Ou-Bong
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.4
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    • pp.12-18
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    • 2008
  • Researches on particle physics have benefited our everyday life in many aspects. They have tested the safety of the objects we use everyday, conducted experiments to examine harmful environments to man, and treated diseases. Despite the usefulness of particle physics in a range of fields, however, it's difficult to conduct researches and experiments directly. But the advancements in the computer industry have allowed for experiments of particle physics in virtual simulations. One of the foremost simulation libraries for particle physics that have been researched actively these days, Geant4 has been put to diverse uses in particle physics. This study designed GUI so that physicists, who were not good at programming, could use a simulation library faster, more accurately, and more conveniently. It also developed the Geant4Editor, a simulation automation framework. The advantages of the Geant4Editor include automatic generations of essential classes in a simulation using Geant4 libraries and real-time reflection of user demands in a simulation. It also allows for efficient management of resources(user-created data) through the Data Manager.

Monte Carlo Simulation for absorbed dose in PMMA phantom during the low-energy X-ray irradiation (저 에너지 X선 조사 시 PMMA 팬텀 내의 흡수선량 평가를 위한 몬테카를로 시뮬레이션)

  • Kim, Sang-Tae;Kang, Sang-Koo;Kim, Chong-Yeal
    • Journal of the Korean Society of Radiology
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    • v.5 no.6
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    • pp.383-389
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    • 2011
  • This study offered a new method to calculate absorbed dose of actual patients through Monte Carlo Simulation by using the linkage of Geant4 and DICOM, and, the experimental value of absorbed dose at the center and Geant 4 simulation result according to the depth of PMMA mock phantom were compared by using MOSEF in order to verify Geant4 calculation code. In the area where there was no air space between the irregular gap due to incomplete compression of PMMA slab, the differences were $0.46{\pm}4.69$ percent and $-0.75{\pm}5.19$percent in $15{\times}15cm^2$ and $20{\times}20cm^2$ respectively. Excluding the error due to incomplete compression of PMMA mock phantom, the calculation values of the Monte Carlo simulation by linkage of Geant4 and DICOM was the same.

Precision Validation of Electromagnetic Physics in Geant4 Simulation for Proton Therapy (양성자 치료 전산모사를 위한 Geant4 전자기 물리 모델 정확성 검증)

  • Park, So-Hyun;Rah, Jeong-Eun;Shin, Jung-Wook;Park, Sung-Yong;Yoon, Sei-Chul;Jung, Won-Gyun;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.20 no.4
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    • pp.225-234
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    • 2009
  • Geant4 (GEometry ANd Tracking) provides various packages specialized in modeling electromagnetic interactions. The validation of Geant4 physics models is a significant issue for the applications of Geant4 based simulation in medical physics. The purpose of this study is to evaluate accuracy of Geant4 electromagnetic physics for proton therapy. The validation was performed both the Continuous slowing down approximation (CSDA) range and the stopping power. In each test, the reliability of the electromagnetic models in a selected group of materials was evaluated such as water, bone, adipose tissue and various atomic elements. Results of Geant4 simulation were compared with the National Institute of Standards and Technology (NIST) reference data. As results of comparison about water, bone and adipose tissue, average percent difference of CSDA range were presented 1.0%, 1.4% and 1.4%, respectively. Average percent difference of stopping power were presented 0.7%, 1.0% and 1.3%, respectively. The data were analyzed through the kolmogorov-smirnov Goodness-of-Fit statistical analysis test. All the results from electromagnetic models showed a good agreement with the reference data, where all the corresponding p-values are higher than the confidence level $\alpha=0.05$ set.

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Verification of Dose Evaluation of Human Phantom using Geant4 Code (Geant4 코드를 사용한 인체팬텀 선량평가 검증)

  • Jang, Eun-Sung;Choi, Ji-Hoon
    • Journal of the Korean Society of Radiology
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    • v.14 no.5
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    • pp.529-535
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    • 2020
  • Geant4 is compatible with the Windows operating system in C++ language use, enabling interface functions that link DICOM or software. It was simulated to address the basic structure of the simulation using Geant4/Gate code and to specifically verify the density composition and lung cancer process in the human phantom. It was visualized using the Gate Graphic System, i.e. openGL, Ray Tracer: Ray Tracing by Geant4 Tracing, and using Geant4/Gate code, lung cancer is modeled in the human phantom area in 3D, 4D to verify the simulation progress. Therefore, as a large number of new functions are added to the Gate Code, it is easy to implement accurate human structure and moving organs.

Geant4-DICOM Interface-based Monte Carlo Simulation to Assess Dose Distributions inside the Human Body during X-Ray Irradiation

  • Kim, Sang-Tae
    • International Journal of Contents
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    • v.8 no.2
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    • pp.52-59
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    • 2012
  • This study uses digital imaging and communications in medicine (DICOM) files acquired after CT scan to obtain the absorbed dose distribution inside the body by using the patient's actual anatomical data; uses geometry and tracking (Geant)4 as a way to obtain the accurate absorbed dose distribution inside the body. This method is easier to establish the radioprotection plan through estimating the absorbed dose distribution inside the body compared to the evaluation of absorbed dose using thermo-luminescence dosimeter (TLD) with inferior reliability and accuracy because many variables act on result values with respect to the evaluation of the patient's absorbed dose distribution in diagnostic imaging and the evaluation of absorbed dose using phantom; can contribute to improving reliability accuracy and reproducibility; it makes significance in that it can implement the actual patient's absorbed dose distribution, not just mere estimation using mathematical phantom or humanoid phantom. When comparing the absorbed dose in polymethly methacrylate (PMMA) phantom measured in metal oxide semiconductor field effect transistor (MOSFET) dosimeter for verification of Geant4 and the result of Geant4 simulation, there was $0.46{\pm}4.69%$ ($15{\times}15cm^2$), and $-0.75{\pm}5.19%$ ($20{\times}20cm^2$) difference according to the depth. This study, through the simulation by means of Geant4, suggests a new way to calculate the actual dose of radiation exposure of patients through DICOM interface.

Development of DICOM Convert Program for the Geant4 Monte Carlo Simulation of the Radiotherapy (방사선치료의 Geant4 전산모사를 위한 DICOM 변환 프로그램 개발)

  • Kang, Jeongku;Lee, Dong Joon
    • Progress in Medical Physics
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    • v.24 no.4
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    • pp.259-264
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    • 2013
  • The DICOM converter program of the Geant4 Monte Carlo simulation code for the application of radiotherapy was developed. We analysis the header part of the DICOM file and find various parameters, such as matrix size, pixel size, stored data bits, high bit, and padding values. Especially we evaluate every pixel value of the DICOM files. To conform the exact convert of the pixel values, we developed the verify program. As a result, the DICOM formats generated from difference CT vendors can be converted and verified for Genat4 calculations.

A Study on Absorbed Dose in the Breast Tissue using Geant4 simulation for Mammography (유방촬영에서 Geant4 시뮬레이션를 이용한 유방조직내 흡수선량에 관한 연구)

  • Lee, Sang-Ho;Lee, Jong-Seok;Han, Sang-Hyun
    • Journal of radiological science and technology
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    • v.35 no.4
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    • pp.345-352
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    • 2012
  • As the breast cancer rate is increasing fast in Korean women, people pay more attention to mammography and number of mammography have been increasing dramatically over the last few years. Mammography is the only means to diagnose breast cancer early, but harms caused by radiation exposure shouldn't be overlooked. Therefore, it is important to calculate the radiation dose being absorbed into the breast tissue during the process of mammography for a protective measure against radiation exposure. Because it is impossible to directly measure the radiation dose being absorbed into the human body, statistical calculation methods are commonly used, and most of them are supposed to simulate the interaction between radiation and matter by describing the human body internal structure with anthropomorphic phantoms. However, a simulation using Geant4 Code of Monte Carlo Method, which is well-known as most accurate in calculating the absorbed dose inside the human body, helps calculate exact dose by recreating the anatomical human body structure as it is through the DICOM file of CT. To calculate the absorbed dose in the breast tissue, therefore, this study carried out a simulation using Geant4 Code, and by using the DICOM converted file provided by Geant4, this study changed the human body structure expressed on the CT image data into geometry needed for this simulation. Besides, this study attempted to verify if the dose calculation of Geant4 interlocking with the DICOM file is useful, by comparing the calculated dose provided by this simulation and the measured dose provided by the PTW ion chamber. As a result, under the condition of 28kVp/190mAs, the Difference(%) between the measured dose and the calculated dose was found to be 0.08 %~0.33 %, and at 28 kVp/70 mAs, the Difference(%) of dose was 0.01 %~0.16 %, both of which showed results within 2%, the effective difference range. Therefore, this study found out that calculation of the absorbed dose using Geant4 Simulation is useful in measuring the absorbed dose in the breast tissue for mammography.